Apparatus, kits, and methods for creating cavities in cancellous bone using an elongated loop structure or bristles

ABSTRACT

Systems and method create a cavity in cancellous bone by use of a system or kit that includes a cannula having an axis that establishes a percutaneous path leading into bone and a shaft having a distal end portion carrying an elongated loop structure or bristles capable of extension from the shaft to create a cavity forming structure. The shaft is movable relative to the axis of the cannula to move the cavity forming structure when extended within cancellous bone to form a cavity in the cancellous bone. A tool is sized for passage through the cannula. The tool is capable of dispensing a filling material into the cavity.

RELATED APPLICATIONS

This application is a divisional of application Ser. No. 11/789,226,filed Apr. 24, 2007, and entitled Apparatus and Methods for CreatingCavities in Interior Body Regions,” which is a divisional of applicationSer. No. 10/958,944, filed Oct. 5, 2004, and entitled “Structures andMethods for Creating Cavities in Interior Body Regions,” (nowabandoned), which is a divisional of application Ser. No. 10/208,391,filed Jul. 30, 2002 (now U.S. Pat. No. 6,863,672), which is a divisionalof application Ser. No. 09/055,805, filed Apr. 6, 1998 (now U.S. Pat.No. 6,440,138), each of which is incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to structures and procedures, which, in use, formcavities in interior body regions of humans and other animals fordiagnostic or therapeutic purposes.

BACKGROUND OF THE INVENTION

Certain diagnostic or therapeutic procedures require the formation of acavity in an interior body region.

For example, as disclosed in U.S. Pat. Nos. 4,969,888 and 5,108,404, anexpandable body is deployed to form a cavity in cancellous bone tissue,as part of a therapeutic procedure that fixes fractures or otherabnormal bone conditions, both osteoporotic and non-osteoporotic inorigin. The expandable body compresses the cancellous bone to form aninterior cavity. The cavity receives a filling material, which providesrenewed interior structural support for cortical bone.

This procedure can be used to treat cortical bone, which due toosteoporosis, avascular necrosis, cancer, or trauma, is fractured or isprone to compression fracture or collapse. These conditions, if notsuccessfully treated, can result in deformities, chronic complications,and an overall adverse impact upon the quality of life.

A demand exists for alternative systems or methods which, like theexpandable body shown in U.S. Pat. Nos. 4,969,888 and 5,108,404, arecapable of forming cavities in bone and other interior body regions insafe and efficacious ways.

SUMMARY OF THE INVENTION

One aspect of the invention provides systems and methods for creating acavity in cancellous bone. The systems and method comprise a cannulahaving an axis that establishes a percutaneous path leading into bone.The systems and method include a shaft having a distal end portioncarrying an elongated loop structure or bristles capable of extensionfrom the shaft to create a cavity forming structure. The shaft is sizedfor passage through the cannula into bone prior to extension of theelongated loop structure or bristles. The systems and methods include acontroller to extend the elongated loop structure or bristles from theshaft in situ within cancellous bone to create the cavity formingstructure. The shaft is movable relative to the axis of the cannula tomove the cavity forming structure when extended within cancellous boneto form a cavity in the cancellous bone. The systems and methods includea tool sized for passage through the cannula, the tool being capable ofdispensing a filling material into the cavity.

Another aspect of the invention provides a kit comprising a cannulahaving an axis that establishes a percutaneous path leading into boneand a shaft having a distal end portion carrying an elongated loopstructure or bristles capable of extension from the shaft to create acavity forming structure. The shaft is sized for passage through thecannula into bone prior to extension of the elongated loop structure orbristles. The kit includes a controller to extend the elongated loopstructure or bristles from the shaft in situ within cancellous bone tocreate the cavity forming structure. The shaft is movable relative tothe axis of the cannula to move the cavity forming structure whenextended within cancellous bone to form a cavity in the cancellous bone.The kit includes a tool sized for passage through the cannula, the toolbeing capable of dispensing a filling material into the cavity. The kitincludes instructions for creating a cavity in cancellous bone bydeploying the cannula percutaneously to establish a path leading intobone, introducing the shaft by movement within and along the axis of thecannula to place the elongated loop structure or bristles insidecancellous bone, extending the cavity forming structure in situ withinthe cancellous bone from the shaft, moving the shaft to form a cavity inthe cancellous bone, and introducing the tool by movement within andalong the axis of the cannula, and conveying filling material throughthe tool into the cavity.

Another aspect of the invention provides media comprising instructionsfor creating a cavity in cancellous bone by deploying a cannula havingan axis that establishes a percutaneous path leading into bone,introducing a shaft having a distal end portion carrying an elongatedloop structure or bristles capable of extension from the shaft to createa cavity forming structure, by movement of the shaft within and alongthe axis of the cannula to place the elongated loop structure orbristles inside cancellous bone, extending the cavity forming structurein situ within the cancellous bone from the shaft, moving the shaft toform a cavity in the cancellous bone, and introducing a tool a toolsized for passage through the cannula, the tool being capable ofdispensing a filling material into the cavity, by movement of the toolwithin and along the axis of the cannula, and conveying filling materialthrough the tool into the cavity.

Features and advantages of the inventions are set forth in the followingDescription and Drawings, as well as in the appended Claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a rotatable tool having a loop structurecapable of forming a cavity in tissue, with the loop structure deployedbeyond the associated catheter tube;

FIG. 1A is an enlarged end view of the tool shown in FIG. 1;

FIG. 2 is a side view of the tool shown in FIG. 1, with the loopstructure retracted within the catheter tube;

FIG. 3 is a side view of the tool shown in FIG. 1, with the loopstructure deployed beyond the catheter tube to a greater extent thanshown in FIG. 1;

FIG. 4 is a side view of the tool shown in FIG. 1 inserted within aguide sheath for deployment in a targeted treatment area;

FIG. 5 is a side view of another rotatable tool having a brush structurecapable of forming a cavity in tissue, with the brush structure deployedbeyond the associated drive tube;

FIG. 5A is an enlarged end view of the tool shown in FIG. 5;

FIG. 6 is a side view of the tool shown in FIG. 5, with the brushstructure retracted within the drive tube;

FIG. 7 is a side view of the tool shown in FIG. 5, with the brushstructure deployed beyond the catheter tube to a greater extent thanshown in FIG. 5, and with the brush structure being rotated to cause theassociated bristles to flare outward;

FIG. 8 is a side view of the tool shown in FIG. 7, with the brushstructure deployed beyond the catheter tube to a greater extent thanshown in FIG. 7, and with the brush structure still being rotated tocause the associated bristles to flare outward;

FIG. 9 is a side view of an alternative tool having an array of bristlescarried by a flexible shaft, which is capable of forming a cavity intissue;

FIG. 10 is a side view of the tool shown in FIG. 9 as it is beingdeployed inside a cannula;

FIG. 11 is the tool shown in FIG. 9 when deployed in a soft tissueregion bounded by hard tissue;

FIG. 12 is a side view of a tool having a rotatable blade structurecapable of forming a cavity in tissue;

FIG. 13 is a side view of an alternative curved blade structure that thetool shown in FIG. 12 can incorporate;

FIG. 14 is a side view of an alternative ring blade structure that thetool shown in FIG. 12 can incorporate;

FIG. 15 is a side view of the ring blade structure shown in FIG. 14while being introduced through a cannula;

FIG. 16 is a side view of a rotating tool capable of forming a cavity intissue, with an associated lumen to introduce a rinsing liquid andaspirate debris;

FIG. 17 is a perspective side view of a tool having a linear movementblade structure capable of forming a cavity in tissue, with the bladestructure deployed beyond the associated catheter tube in an operativeposition for use;

FIG. 18 is an end view of the tool shown in FIG. 17, with the bladestructure shown in its operative position for use;

FIG. 19 is an end view of the tool shown in FIG. 17, with the bladestructure shown in its rest position within the catheter tube;

FIG. 20 is a side view of the tool shown in FIG. 17, with the bladestructure shown in its rest position within the catheter tube, as alsoshown in an end view in FIG. 18;

FIG. 21 is a side view of the tool shown in FIG. 17, with the bladestructure deployed beyond the associated catheter tube in an operativeposition for use, as also shown in an end view in FIG. 18;

FIG. 22 is a side view of a tool having a linear movement energytransmitter capable of forming a cavity in tissue, with the energytransmitter deployed beyond the associated catheter tube in an operativeposition for use;

FIG. 23 is a top view of a human vertebra, with portions removed toreveal cancellous bone within the vertebral body, and with a guidesheath located for postero-lateral access;

FIG. 24 is a side view of the vertebra shown in FIG. 23;

FIG. 25 is a top view of the vertebra shown in FIG. 23, with the toolshown in FIG. 1 deployed to cut cancellous bone by rotating the loopstructure, thereby forming a cavity;

FIG. 26 is a top view of the vertebra shown in FIG. 23, with the toolshown in FIG. 5 deployed to cut cancellous bone by rotating the brushstructure, thereby forming a cavity;

FIG. 27 is a side view of the vertebra shown in FIG. 23, with the toolshown in FIG. 17 deployed to cut cancellous bone by moving the bladestructure in a linear path, thereby forming a cavity;

FIG. 28 is a side view of the vertebra shown in FIG. 23, with the toolshown in FIG. 22 deployed to cut cancellous bone using an energytransmitter, which is both rotatable and movable in a linear path,thereby forming a cavity;

FIG. 29 is a side view of the vertebra shown in FIG. 23, after formationof a cavity by use of one of the tools shown in FIGS. 25 to 28, and witha second tool deployed to introduce material into the cavity fortherapeutic purposes;

FIG. 30 is a plan view of a sterile kit to store a single use cavityforming tool of a type previously shown; and

FIG. 31 is an exploded perspective view of the sterile kit shown in FIG.30.

The invention may be embodied in several forms without departing fromits spirit or essential characteristics. The scope of the invention isdefined in the appended claims, rather than in the specific descriptionpreceding them. All embodiments that fall within the meaning and rangeof equivalency of the claims are therefore intended to be embraced bythe claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The systems and methods embodying the invention can be adapted for usevirtually in any interior body region, where the formation of a cavitywithin tissue is required for a therapeutic or diagnostic purpose. Thepreferred embodiments show the invention in association with systems andmethods used to treat bones. This is because the systems and methodswhich embody the invention are well suited for use in this environment.It should be appreciated that the systems and methods which embodyfeatures of the invention can be used in other interior body regions, aswell.

I. Rotatable Cavity Forming Structures

A. Rotatable Loop Structure

FIG. 1 shows a rotatable tool 10 capable of forming a cavity in atargeted treatment area. The tool 10 comprises a catheter tube 12 havinga proximal and a distal end, respectively 14 and 16. The catheter tube12 preferable includes a handle 18 to aid in gripping and maneuveringthe tube 12. The handle 18 can be made of a foam material secured aboutthe catheter tube 12.

The catheter tube 12 carries a cavity forming structure 20 at its distalend 16. In the illustrated embodiment, the structure 20 comprises afilament 22 of resilient inert material, which is bent back upon itselfand preformed with resilient memory to form a loop.

The material from which the filament 22 is made can be resilient, inertwire, like stainless steel. Alternatively, resilient injection moldedinert plastic or shape memory material, like nickel titanium(commercially available as Nitinol™ material), can also be used. Thefilament 22 can, in cross section, be round, rectilinear, or an otherconfiguration.

As FIG. 1A shows, the filament 22 radiates from slots 24 in a base 26carried by the distal end 16 of the catheter tube 12. The free ends 28of the filament 22 extend through the catheter tube 12 and are connectedto a slide controller 30 near the handle 18.

As FIG. 2 shows, sliding the controller 30 aft (arrow A) retracts thefilament 22 through the slots 24, which progressively decreases thedimensions of the loop structure 20. As FIG. 2 shows, in its farthestaft position, the filament 22 is essentially fully withdrawn and doesnot project a significant distance beyond the distal end 16 of thecatheter tube 12.

As FIG. 3 shows, sliding the controller 30 forward (arrow F) advancesthe filament 22 through the slots 24. The loop structure 20 forms, whichprojects beyond the distal end 16 of the catheter tube 12. As it isadvanced progressively forward through the slots 24, the dimensions ofthe loop structure 20 progressively increase (compare FIG. 1 to FIG. 3).The controller 30 can include indicia 32, through which the physiciancan estimate the dimensions of the loop structure 20.

In use (see FIG. 4), the catheter tube 12 is carried for axial androtational movement within a guide sheath or cannula 34. The physicianis able to freely slide the catheter tube 12 axially within the guidesheath 34 (arrow S in FIG. 4). As FIG. 4 shows, when fully confined bythe guide sheath 34, the loop structure 20, if projecting a significantdistance beyond the distal end 16, is collapsed by the surroundingsheath 34. When free of the guide sheath 34, the loop structure 20springs open to assume its normal dimension. Thereafter, the physiciancan operate the controller 30 to alter the dimension of the loopstructure 20 at will.

When free of the guide sheath 34, the physician is also able to rotatethe deployed loop structure 20, by rotating the catheter tube 12 withinthe guide sheath 34 (arrow R in FIG. 4). As will be described in greaterdetail alter, rotation of the loop structure 20 slices or cut throughsurrounding tissue mass.

The materials for the catheter tube 12 are selected to facilitateadvancement and rotation of the loop structure 20. The catheter tube 12can be constructed, for example, using standard flexible, medical gradeplastic materials, like vinyl, nylon, polyethylenes, ionomer,polyurethane, and polyethylene tetraphthalate (PET). The catheter tube12 can also include more rigid materials to impart greater stiffness andthereby aid in its manipulation and torque transmission capabilities.More rigid materials that can be used for this purpose include stainlesssteel, nickel-titanium alloys (Nitinol™ material), and other metalalloys.

The filament 22 preferably carries one or more radiological markers 36.The markers 36 are made from known radiopaque materials, like platinum,gold, calcium, tantalum, and other heavy metals. At least one marker 36is placed at or near the distal extremity of the loop structure 20,while other markers can be placed at spaced apart locations on the loopstructure 20. The distal end 16 of the catheter tube 12 can also carrymarkers. The markers 36 permit radiologic visualization of the loopstructure 20 and catheter tube 12 within the targeted treatment area.

Of course, other forms of markers can be used to allow the physician tovisualize the location and shape of the loop structure 20 within thetargeted treatment area.

B. Rotatable Brush

FIG. 5 shows an alternative embodiment of a rotatable tool 38 capable offorming a cavity in a targeted treatment area. The tool 38 comprises adrive shaft 40, which is made from stiffer materials for good torsiontransmission capabilities, e.g., stainless steel, nickel-titanium alloys(Nitinol™ material), and other metal alloys.

The distal end 42 of the drive shaft carries a cavity forming structure44, which comprises an array of filaments forming bristles 46. As FIG.5A shows, the bristles 46 extend from spaced-apart slots 48 in a base 50carried by the distal end 42 of the drive shaft 40.

The material from which the bristles 46 is made can be stainless steel,or injection molded inert plastic, or shape memory material, like nickeltitanium. The bristles 46 can, in cross section, be round, rectilinear,or an other configuration.

The proximal end 52 of the drive shaft 40 carries a fitting 54 that, inuse, is coupled to an electric motor 56 for rotating the drive shaft 40,and, with it, the bristles 46 (arrows R in FIGS. 7 and 8). When rotatedby the motor 46, the bristles spread apart (as FIG. 7 shows), under theinfluence of centrifugal force, forming a brush-like structure 44. Thebrush structure 44, when rotating, cuts surrounding tissue mass in thetargeted treatment area.

The free ends 58 of the bristles 46 extend through the drive shaft 40and are commonly connected to a slide controller 60. As FIG. 6 shows,sliding the controller 60 aft (arrow A in FIG. 6) shortens the distancethe bristles 46 extend from the base 50. As FIGS. 7 and 8 show, slidingthe controller 60 forward (arrow F in FIG. 8) lengthens the extensiondistance of the bristles 46. Using the controller 60, the physician isable to adjust the dimension of the cutting area (compare FIG. 7 andFIG. 8).

The array of bristles 46 preferably includes one or more radiologicalmarkers 62, as previously described. The markers 62 allow radiologicvisualization of the brush structure 44 while in use within the targetedtreatment area. The controller 60 can also include indicia 64 by whichthe physician can visually estimate the bristle extension distance. Thedistal end 42 of the drive shaft 40 can also carry one or more markers62.

The drive shaft 40 of the tool 38 is, in use, carried for axial androtational movement within the guide sheath or cannula 34, in the samemanner shown for the tool 10 in FIG. 4. The physician is able to freelyslide the drive shaft 40 axially within the guide sheath to deploy it inthe targeted treatment area. Once connected to the drive motor 56, thedrive shaft 40 is free to rotate within the guide sheath 34 to form thebrush structure 44.

FIG. 9 shows an alternative embodiment of a rotatable tool 138 having anarray of filaments forming bristles 140, which is capable of forming acavity in a targeted treatment area. The tool 138 includes a flexibledrive shaft 142, which is made, e.g., from twisted wire filaments, suchstainless steel, nickel-titanium alloys (Nitinol™ material), and othermetal alloys.

The bristles 140 radially extend from the drive shaft 142, near itsdistal end. The bristles 140 can be made, e.g., from resilient stainlesssteel, or injection molded inert plastic, or shape memory material, likenickel titanium. The bristles 140 can, in cross section, be round,rectilinear, or an other configuration.

As FIG. 10 shows, the tool 138 is introduced into the targeted tissueregion through a cannula 144. When in the cannula 144, the resilientbristles 140 are compressed rearward to a low profile, enabling passagethrough the cannula. When free of the cannula 144, the resilientbristles 140 spring radially outward, ready for use.

The proximal end of the drive shaft 142 carries a fitting 146 that, inuse, is coupled to an electric motor 148. The motor 148 rotates thedrive shaft 142 (arrow R in FIG. 11), and, with it, the bristles 140.

As FIG. 11 shows, when deployed inside an interior body cavity with softtissue S (e.g., cancellous bone bounded by hard tissue H (e.g., corticalbone), the physician can guide the tool 138 through the soft tissue S byallowing the rotating bristles 140 to ride against the adjoining hardtissue H. The flexible drive shaft 142 bends to follow the contour ofthe hard tissue H, while the rotating bristles 140 cut adjoining softtissue S, forming a cavity C.

In the illustrated embodiment, the drive shaft 142 carries a pitchedblade 151 at its distal end. The blade 151 rotates with the drive shaft142. By engaging tissue, the blade 151 generates a forward-pullingforce, which helps to advance the drive shaft 142 and bristles 140through the soft-tissue mass.

In the illustrated embodiment, the bristles 140, or the cannula 144, orboth include one or more radiological markers 153, as previouslydescribed. The markers 153 allow radiologic visualization of thebristles 140 while rotating and advancing within the targeted treatmentarea.

C. Rotatable Blade Structure

FIG. 12 shows an alternative embodiment of a rotatable tool 106 capableof forming a cavity in a targeted treatment area. The tool 106, like thetool 38, comprises a generally stiff drive shaft 108, made from, e.g.,stainless steel, nickel-titanium alloys (Nitinol™ material), and othermetal alloys, for good torsion transmission capabilities.

The distal end of the drive shaft 108 carries a cavity forming structure110, which comprises a cutting blade. The blade 110 can take variousshapes.

In FIGS. 12 and 13, the blade 110 is generally L-shaped, having a mainleg 112 and a short leg 116. In the illustrated embodiment, the main leg112 of the blade 110 is pitched radially forward of the drive shaft axis114, at a small forward angle beyond perpendicular to the drive shaft.The main leg 112 may possess a generally straight configuration (as FIG.12 shows), or, alternatively, it may present a generally curved surface(as FIG. 13 shows). In the illustrated embodiment, the short leg 116 ofthe blade 110 is also pitched at a small forward angle from the main leg112, somewhat greater than perpendicular.

In FIG. 14, the blade 110 takes the shape of a continuous ring 126. Asillustrated, the ring 126 is pitched slightly forward, e.g., at an angleslightly greater than perpendicular relative to the drive shaft axis114.

The material from which the blade 110 is made can be stainless steel, orinjection molded inert plastic. The legs 112 and 116 of the blade 110shown in FIGS. 12 and 13, and the ring 126 shown in FIG. 14, can, incross section, be round, rectilinear, or another configuration.

When rotated (arrow R), the blade 110 cuts a generally cylindrical paththrough surrounding tissue mass. The forward pitch of the blade 110reduces torque and provides stability and control as the blade 110advances, while rotating, through the tissue mass.

Rotation of the blade 110 can be accomplished manually or at higherspeed by use of a motor. In the illustrated embodiment, the proximal endof the drive shaft 108 of the tool 106 carries a fitting 118. Thefitting 118 is coupled to an electric motor 120 to rotate the driveshaft 108, and, with it, the blade 110.

As FIG. 15 shows, the drive shaft 108 of the tool 108 is deployedsubcutaneously into the targeted tissue area through a guide sheath orcannula 124. Connected to the drive motor 120, the drive shaft 108rotates within the guide sheath 34, thereby rotating the blade 110 tocut a cylindrical path P in the surrounding tissue mass TM. The blade110 can be advanced and retracted, while rotating, in a reciprocal path(arrows F and A), by applying pushing and pulling forces upon the driveshaft 108. The blade 110 can also be withdrawn into the cannula 124 toallow changing of the orientation of the cannula 124. In this way,successive cylindrical paths can be cut through the tissue mass, throughrotating and reciprocating the blade 110, to thereby create a desiredcavity shape.

The blade 110, or the end of the cannula 124, or both can carry one ormore radiological markers 122, as previously described. The markers 122allow radiologic visualization of the blade 110 and its positionrelative to the cannula 34 while in use within the targeted treatmentarea.

D. Rinsing and Aspiration

As FIG. 16 shows, any of the tools 10, 38, 106, or 138 can include aninterior lumen 128. The lumen 128 is coupled via a Y-valve 132 to aexternal source 130 of fluid and an external vacuum source 134.

A rinsing liquid 136, e.g., sterile saline, can be introduced from thesource 130 through the lumen 128 into the targeted tissue region as thetools 10, 38, or 106 rotate and cut the tissue mass TM. The rinsingliquid 136 reduces friction and conducts heat away from the tissueduring the cutting operation. The rinsing liquid 136 can be introducedcontinuously or intermittently while the tissue mass is being cut. Therinsing liquid 136 can also carry an anticoagulant or otheranti-clotting agent.

By periodically coupling the lumen 128 to the vacuum source 134, liquidsand debris can be aspirated from the targeted tissue region through thelumen 128.

II. Linear Movement Cavity Forming Structures

A. Cutting Blade

FIGS. 17 to 21 show a linear movement tool 66 capable of forming acavity in a targeted treatment area. Like the tool 10, the tool 66comprises a catheter tube 68 having a handle 70 (see FIG. 20) on itsproximal end 72 to facilitate gripping and maneuvering the tube 68.

The catheter tube 68 carries a linear movement cavity forming structure74 at its distal end 76. In the illustrated embodiment, the structure 56comprises a generally rigid blade 78, which projects at a side anglefrom the distal end 76 (see FIGS. 17 and 21). The blade 78 can be formedfrom stainless steel or cast or molded plastic.

A stylet 80 is carried by an interior track 82 within the catheter tube68 (see FIGS. 18 and 19). The track 82 extends along the axis of thecatheter tube 68. The stylet 80 is free to move in a linear aft path(arrow A in FIG. 20) and a linear forward path (arrow F in FIG. 21)within the track 82. The stylet 80 is also free to rotate within thetrack 82 (arrow R in FIG. 17).

The far end of the stylet 80 is coupled to the blade 78. The near end ofthe stylet 80 carries a control knob 84. By rotating the control knob84, the physician rotates the blade 78 between an at rest position,shown in FIGS. 19 and 20, and an operating position, shown in FIGS. 17,18, and 21. When in the at rest position, the physician can push or pullupon the control knob 84 to move the blade 78 in a linear path withinthe catheter tube (see FIG. 20). By pushing on the control knob 84, thephysician can move the blade 78 outside the catheter tube 68, where itcan be rotated into the operating condition (see FIG. 21). When in theoperating position, pushing and pulling on the control knob 84 moves theblade in linear strokes against surrounding tissue mass.

In use, the catheter tube 68 is also carried for sliding and rotationwithin the guide sheath or cannula 34, in the same manner shown in FIG.4. The physician is able to freely slide the catheter tube 68 axiallywithin the guide sheath 34 to deploy the tool 66 in the targetedtreatment site. When deployed at the site, the physician can deploy theblade 78 in the operating condition outside the catheter tube 68 andslide the blade 78 along tissue in a linear path. Linear movement of theblade 78 along tissue cuts the tissue. The physician is also able torotate both the catheter tube 68 within the guide sheath 34 and theblade 78 within the catheter tube 68 to adjust the orientation andtravel path of the blade 78.

The blade 78 can carry one or more radiological markers 86, aspreviously described, to allow radiologic visualization of the blade 78within the targeted treatment area. Indicia 88 on the stylet 80 can alsoallow the physician to visually approximate the extent of linear orrotational movement of the blade 78. The distal end 76 of the cathetertube 68 can also carry one or more markers 86.

B. Energy Transmitters

FIG. 22 shows an alternative embodiment of a linear movement tool 90capable of forming a cavity in a targeted treatment area. The tool 90 isphysically constructed in the same way as the linear movement tool 66just described, so common reference numerals are assigned.

However, for the tool 90 shown FIG. 22, the far end of the stylet 80carries, not a cutting blade 78, but instead a transmitter 92 capable oftransmitting energy that cuts tissue (shown by lines 100 in FIG. 22). Aconnector 94 couples the transmitter 92 to a source 96 of the energy,through a suitable energy controller 98.

The type of energy 100 that the transmitter 92 propagates to removetissue in the targeted treatment area can vary. For example, thetransmitter 92 can propagate ultrasonic energy at harmonic frequenciessuitable for cutting the targeted tissue. Alternatively, the transmitter92 can propagate laser energy at a suitable tissue cutting frequency.

As before described, the near end of the stylet 80 includes a controlknob 84. Using the control knob 84, the physician is able to move thetransmitter 92 in a linear path (arrows A and F in FIG. 22) between aretracted position, housed with the catheter tube 68 (like the blade 78shown in FIG. 20), and a range of extended positions outside thecatheter tube 68, as shown in FIG. 22).

As also described before, the catheter tube 68 of the tool 90 is, inuse, carried for sliding and rotation within the guide sheath or cannula34. The physician slides the catheter tube 68 axially within the guidesheath 34 for deployment of the tool 90 at the targeted treatment site.When deployed at the site, the physician operates the control knob 84 tolinearly move and rotate the transmitter 92 to achieve a desiredposition in the targeted treatment area. The physician can also rotatethe catheter tube 68 and thereby further adjust the location of thetransmitter 92.

The transmitter 92 or stylet 80 can carry one or more radiologicalmarkers 86, as previously described, to allow radiologic visualizationof the position of the transmitter 92 within the targeted treatmentarea. Indicia 88 on the stylet 80 can also allow the physician tovisually estimate the position of the transmitter 92. The distal end 76of the catheter tube 68 can also carry one or more markers 86.

III. Use of Cavity Forming Tools

Use of the various tools 10 (FIGS. 1 to 4), 38 (FIGS. 5 to 8), 138(FIGS. 9 to 11), 106 (FIGS. 12 to 15), 66 (FIGS. 17 to 21), and 90 (FIG.22) will now be described in the context of deployment in a humanvertebra 150.

FIG. 23 shows the vertebra 150 in coronal (top) view, and FIG. 24 showsthe vertebra 150 in lateral (side) view. It should be appreciated,however, the tool is not limited in its application to vertebrae. Thetools 10, 38, 138, 106, 66, and 90 can be deployed equally as well inlong bones and other bone types.

As FIGS. 23 and 24 show, the vertebra 150 includes a vertebral body 152,which extends on the anterior (i.e., front or chest) side of thevertebra 150. The vertebral body 152 includes an exterior formed fromcompact cortical bone 158. The cortical bone 158 encloses an interiorvolume of reticulated cancellous, or spongy, bone 160 (also calledmedullary bone or trabecular bone).

The vertebral body 152 is in the shape of an oval disk. As FIGS. 23 and24 show, access to the interior volume of the vertebral body 152 can beachieved. e.g., by drilling an access portal 162 through a side of thevertebral body 152, which is called a postero-lateral approach. Theportal 162 for the postero-lateral approach enters at a posterior sideof the body 152 and extends at angle forwardly toward the anterior ofthe body 152. The portal 162 can be performed either with a closed,minimally invasive procedure or with an open procedure.

Alternatively, access into the interior volume can be accomplished bydrilling an access portal through either pedicle 164 (identified in FIG.23). This is called a transpedicular approach. It is the physician whoultimately decides which access site is indicated.

As FIGS. 23 and 24 show, the guide sheath 34 (earlier shown in FIG. 4)is located in the access portal 162. Under radiologic or CT monitoring,a selected one of the tools 10, 38, 66, or 90 can be introduced throughthe guide sheath 34.

A. Deployment and Use of the Loop Tool in a Vertebral Body

When, for example, the loop tool 10 is used, the loop structure 20 is,if extended, collapsed by the guide sheath 34 (as shown in FIG. 4), orotherwise retracted within the catheter tube 12 (as FIG. 2 shows) duringpassage through the guide sheath 34.

Referring to FIG. 25, when the loop tool 10 is deployed outside theguide sheath 34 in the cancellous bone 160, the physician operates thecontroller 30 in the manner previously described to obtain a desireddimension for the loop structure 20, which can be gauged by radiologicmonitoring using the on-board markers 36. The physician manually rotatesthe loop structure 20 through surrounding cancellous bone 160 (asindicated by arrows R in FIG. 25). The rotating loop structure 20 cutscancellous bone 160 and thereby forms a cavity C. A suction tube 102,also deployed through the guide sheath 34, removes cancellous bone cutby the loop structure 20. Alternatively, the catheter tube 12 caninclude an interior lumen 128 (as shown in FIG. 16) to serve as asuction tube as well as to convey a rinsing liquid into the cavity as itis being formed.

Synchronous rotation and operation of the controller 30 to enlarge thedimensions of the loop structure 20 during the procedure allows thephysician to achieve a create a cavity C of desired dimension.Representative dimensions for a cavity C will be discussed in greaterdetail later.

B. Deployment and Use of the Brush Tool in a Vertebral Body

When, for example, the brush tool 38 is used, the physician preferablewithdraws the bristles 46 during their passage through the guide sheath34, in the manner shown in FIG. 6.

Referring to FIG. 26, when the brush tool 38 is deployed in cancellousbone 160 free of the guide sheath 34, the physician advances thebristles 46 a desired distance (as shown in FIG. 5), aided by radiologicmonitoring of the markers 62, or the indicia 32 previously described, orboth. The physician connects the drive shaft 40 to the motor 56 torotate the bristles 46, creating the brush structure 44. As FIG. 26shows, the rotating brush structure 44 cuts cancellous bone 160 andforms a cavity C. The suction tube 102 (or a lumen 128 in the driveshaft 40, as shown in FIG. 16) introduces a rinsing fluid (with ananticoagulant, if desired) and removes cancellous bone cut by the brushstructure 44. By periodically stopping rotation of the brush structure44 and operating the controller 60 (previously described) to increasethe forward extension of the bristles 46, the physician able over timeto create a cavity C having the desired dimensions.

C. Deployment and Use of the Linear Tools in a Vertebral Body

When, for example, one of the linear movement tools 66 or 90 are used,the physician preferable withdraws the blade 78 or the transmitter 92into the catheter tube 68 in the manner shown in FIG. 20, until thedistal end 76 of the catheter tube 68 is free of the guide sheath 34.

Referring to FIG. 27, using the blade tool 66, the physician operatesthe stylet 80 forward (arrow F) and aft (arrow A) to move the blade 78in a linear path through cancellous bone 160. The blade 78 scrapes looseand cuts cancellous bone 160 along its path, which the suction tube 102removes. A cavity C is thereby formed. Synchronous rotation (arrow R)and linear movement (arrows F and A) of the blade 78 allow the physicianto create a cavity C having a desired dimension.

Referring to FIG. 28, using the energy transmitting tool 90, thephysician rotates (arrow R) and pushes or pulls upon the stylet 80(arrows F and A) to position the energy transmitter 92 at desiredlocations in cancellous bone 160. The markers 86 aid the locationprocess. Transmission by the transmitter 92 of the selected energy cutscancellous bone 160 for removal by the suction tube 102. A cavity C isthereby formed. Through purposeful maneuvering of the transmitter 92,the physician achieves a cavity C having the desired dimension.

D. Deployment of Other Tools into the Cavity

Once the desired cavity C is formed, the selected tool 10, 38, 66, 90,106, or 138 is withdrawn through the guide sheath 34. As FIG. 29 shows,an other tool 104 can now be deployed through the guide sheath 34 intothe formed cavity C. The second tool 104 can, for example, perform adiagnostic procedure. Alternatively, the second tool 104 can perform atherapeutic procedure, e.g., by dispensing a material 106 into thecavity C, such as, e.g., bone cement, allograft material, synthetic bonesubstitute, a medication, or a flowable material that sets to a hardenedcondition. Further details of the injection of such materials 106 intothe cavity C for therapeutic purposes are found in U.S. Pat. Nos.4,969,888 and 5,108,404 and in copending U.S. patent application Ser.No. 08/485,394, which are incorporated herein by reference.

E. Bone Cavity Dimensions

The size of the cavity C varies according to the therapeutic ordiagnostic procedure performed.

At least about 30% of the cancellous bone volume needs to be removed incases where the bone disease causing fracture (or the risk of fracture)is the loss of cancellous bone mass (as in osteoporosis). The preferredrange is about 30% to 90% of the cancellous bone volume. Removal of lessof the cancellous bone volume can leave too much of the diseasedcancellous bone at the treated site. The diseased cancellous boneremains weak and can later collapse, causing fracture, despitetreatment.

However, there are times when a lesser amount of cancellous bone removalis indicated. For example, when the bone disease being treated islocalized, such as in avascular necrosis, or where local loss of bloodsupply is killing bone in a limited area, the selected tool 10, 38, 66,90, 106, or 138 can remove a smaller volume of total bone. This isbecause the diseased area requiring treatment is smaller.

Another exception lies in the use of a selected tool 10, 36, 66, 90,106, or 138 to improve insertion of solid materials in defined shapes,like hydroxyapatite and components in total joint replacement. In thesecases, the amount of tissue that needs to be removed is defined by thesize of the material being inserted.

Yet another exception lays the use of a selected tool 10, 36, 66, 90,106, or 138 in bones to create cavities to aid in the delivery oftherapeutic substances, as disclosed in copending U.S. patentapplication Ser. No. 08/485,394. In this case, the cancellous bone mayor may not be diseased or adversely affected. Healthy cancellous bonecan be sacrificed by significant compaction to improve the delivery of adrug or growth factor which has an important therapeutic purpose. Inthis application, the size of the cavity is chosen by the desired amountof therapeutic substance sought to be delivered. In this case, the bonewith the drug inside is supported while the drug works, and the boneheals through exterior casting or current interior or exterior fixationdevices.

IV. Single Use Sterile Kit

A single use of any one of the tools 10, 38, 138, 106, 66, or 90 createscontact with surrounding cortical and cancellous bone. This contact candamage the tools, creating localized regions of weakness, which mayescape detection. The existence of localized regions of weakness canunpredictably cause overall structural failure during a subsequent use.

In addition, exposure to blood and tissue during a single use can entrapbiological components on or within the tools. Despite cleaning andsubsequent sterilization, the presence of entrapped biologicalcomponents can lead to unacceptable pyrogenic reactions.

As a result, following first use, the tools may not meet establishedperformance and sterilization specifications. The effects of materialstress and damage caused during a single use, coupled with thepossibility of pyrogen reactions even after resterilization, reasonablyjustify imposing a single use restriction upon the tools for deploymentin bone.

To protect patients from the potential adverse consequences occasionedby multiple use, which include disease transmission, or material stressand instability, or decreased or unpredictable performance, each singleuse tool 10, 38, 66, 90, 106, or 138 is packaged in a sterile kit 500(see FIGS. 30 and 31) prior to deployment in bone.

As FIGS. 30 and 31 show, the kit 500 includes an interior tray 508. Thetray 508 holds the particular cavity forming tool (genericallydesignated 502) in a lay-flat, straightened condition duringsterilization and storage prior to its first use. The tray 508 can beformed from die cut cardboard or thermoformed plastic material. The tray508 includes one or more spaced apart tabs 510, which hold the tool 502in the desired lay-flat, straightened condition.

The kit 500 includes an inner wrap 512, which is peripherally sealed byheat or the like, to enclose the tray 508 from contact with the outsideenvironment. One end of the inner wrap 512 includes a conventionalpeal-away seal 514 (see FIG. 31), to provide quick access to the tray508 upon instance of use, which preferably occurs in a sterileenvironment, such as within an operating room.

The kit 500 also includes an outer wrap 516, which is also peripherallysealed by heat or the like, to enclosed the inner wrap 512. One end ofthe outer wrap 516 includes a conventional peal-away seal 518 (see FIG.31), to provide access to the inner wrap 512, which can be removed fromthe outer wrap 516 in anticipation of imminent use of the tool 502,without compromising sterility of the tool 502 itself.

Both inner and outer wraps 512 and 516 (see FIG. 31) each includes aperipherally sealed top sheet 520 and bottom sheet 522. In theillustrated embodiment, the top sheet 520 is made of transparent plasticfilm, like polyethylene or MYLAR™ material, to allow visualidentification of the contents of the kit 500. The bottom sheet 522 ismade from a material that is permeable to EtO sterilization gas, e.g.,TYVEC™ plastic material (available from DuPont).

The sterile kit 500 also carries a label or insert 506, which includesthe statement “For Single Patient Use Only” (or comparable language) toaffirmatively caution against reuse of the contents of the kit 500. Thelabel 506 also preferably affirmatively instructs againstresterilization of the tool 502. The label 506 also preferably instructsthe physician or user to dispose of the tool 502 and the entire contentsof the kit 500 upon use in accordance with applicable biological wasteprocedures. The presence of the tool 502 packaged in the kit 500verifies to the physician or user that the tool 502 is sterile and hasnot be subjected to prior use. The physician or user is thereby assuredthat the tool 502 meets established performance and sterilityspecifications, and will have the desired configuration when expandedfor use.

The kit 500 also preferably includes directions for use 524, whichinstruct the physician regarding the use of the tool 502 for creating acavity in cancellous bone in the manners previously described. Forexample, the directions 524 instruct the physician to deploy andmanipulate the tool 502 inside bone to cut cancellous bone and form acavity. The directions 524 can also instruct the physician to fill thecavity with a material, e.g., bone cement, allograft material, syntheticbone substitute, a medication, or a flowable material that sets to ahardened condition.

The features of the invention are set forth in the following claims.

1. A system for creating a cavity in cancellous bone comprising acannula having an axis that establishes a percutaneous path leading intobone, a shaft having a distal end portion carrying an elongated loopstructure capable of extension from the shaft to create a cavity formingstructure, the shaft being sized for passage through the cannula intobone prior to extension of the elongated loop structure, a controller toextend the elongated loop structure from the shaft in situ withincancellous bone to create the cavity forming structure, the shaft beingrotatable relative to the cannula about its axis to correspondinglyrotate the cavity forming structure, when extended within cancellousbone, to form a cavity in the cancellous bone, and a tool sized forpassage through the cannula, the tool being capable of dispensing afilling material into the cavity.
 2. A system according to claim 1,wherein the elongated loop carries one or more radiological markers. 3.A system according to claim 1, wherein the shaft comprises a flexiblematerial.
 4. A system according to claim 1, wherein the elongated loopstructure comprises a metal material.
 5. A system according to claim 1,wherein the elongated loop comprises a plastic material.
 6. A systemaccording to claim 1, wherein the elongated loop structure comprises ashape memory material.
 7. A kit comprising a cannula having an axis thatestablishes a percutaneous path leading into bone, a shaft having adistal end portion carrying an elongated loop structure capable ofextension from the shaft to create a cavity forming structure, the shaftbeing sized for passage through the cannula into bone prior to extensionof the elongated loop structure, a controller to extend the elongatedloop structure from the shaft in situ within cancellous bone to createthe cavity forming structure, the shaft being rotatable relative to thecannula about its axis to correspondingly rotate the cavity formingstructure, when extended within cancellous bone, to form a cavity in thecancellous bone, a tool sized for passage through the cannula, the toolbeing capable of dispensing a filling material into the cavity, andinstructions for creating a cavity in cancellous bone by deploying thecannula percutaneously to establish a path leading into bone,introducing the shaft by movement within and along the axis of thecannula to place the elongated loop structure inside cancellous bone,extending the cavity forming structure in situ within the cancellousbone from the shaft, moving the shaft to form a cavity in the cancellousbone, and introducing the tool by movement within and along the axis ofthe cannula, and conveying filling material through the tool into thecavity.
 8. A kit according to claim 7, wherein the elongated loopstructure carries one or more radiological markers.
 9. A kit accordingto claim 7, wherein the shaft comprises a flexible material.
 10. A kitaccording to claim 7, wherein the elongated loop structure comprises ametal material.
 11. A kit according to claim 7, wherein the elongatedloop comprises a plastic material.
 12. A kit according to claim 7,wherein the elongated loop structure comprises a shape memory material.